Of relatively recent vintage is a gun ammunition projectile which is fabricated from two or more metal powders. In one embodiment, the metal powders are die-pressed into an elongated symmetrical generally cylindrical geometry. Such pressed compacts are at times referred to as “cores”. In this embodiment, to form a projectile, a core is placed in a hollow cup-shaped metal jacket having one end thereof closed and its opposite end open for the receipt of the core. After the core has been placed in the jacket, it may be seated against the closed end of jacket. In one embodiment, which employs the cores of the prior art, a disc which has been formed externally of the projectile is introduced into the metal jacket on top of with a core. Thereafter, the jacket/core/disc sub assembly is die-formed to define an ogive on the open end of the jacket, and that end of the core adjacent the open end of the jacket. The formation of the ogive tends to partially crush that portion of the core which is involved in the formation of the ogive, generating unbonded and “semi-bonded” metal powder adjacent the leading end of the projectile. In those projectiles where the ogive end of the projectile is not fully closed, this unbonded or semi-bonded powder is free to escape from the jacket, or to move about within the ogive end of the jacket, during handling of a round of ammunition, while the round is in a gun, and/or after the round has been fired and the projectile is traveling to a target. In the course of this ogive forming operation, the disc is deformed and seals the open end of the jacket against the escape of powder particles from the jacket and is urged against the core to anchor the core and any “loose” powder particles against movement of the core or “loose” particles within and relative to the jacket.
In U.S. Pat. No. 5,789,698, the present inventor disclosed the use of a solid metal disc disposed within the jacket adjacent the exposed end of the core prior to formation of the ogive. As the ogive is formed, this disc is also deformed and urged toward the open end of the jacket where it defines a cap which seals the open end of the jacket to prevent the escape of metal powder from the ogive end of the projectile and/or to preclude migration of loose powder non-uniformly radially of the longitudinal axis (the spin axis) of the projectile.